linuxcnc-esp32 Software Stepping over Ethernet Using ESP32

store.mesanet.com/index.php?route=produc...oduct&product_id=311 shows 19 in stock today of the 7i96, they have quantity pricing.

Cncninja wrote: My plan is to make a dedicated PCB for the RPI 4 Compute module with dedicated step gen processer whether its an LPC or STM32 etc

I don't think that you need a second processor. PCW has pointed out previously that there are stepper driver chips that accept SPI.
Trinamic offer stepper driver ICs that can handle up to 2A or 60V (sadly not both at the same time) and that can be controlled by SPI or UART.
www.trinamic.com/products/integrated-circuits/#c2378

A few of those on the board, a Pi compute module and a bunch of sockets and you would have an all-in-one solution for stepper motors.

andypugh wrote: I don't think that you need a second processor. PCW has pointed out previously that there are stepper driver chips that accept SPI.

(I am assuming that this means that a step-rate update in the 1kHz servo thread would work, and there would be no need for a base thread)

Yes both the STM PowerStep and Trinamic chips have a profile generator
so can run in velocity mode with SPI interface

The point and feature of using the esp32 is that it connects over UDP so there can be a good distance between the motion controller and the stepgens.

If you want minimal parts count then look at AllwinCNC
forum.linuxcnc.org/18-computer/39037-lin...-orange-pi-allwincnc
It has the LCNC motion controller, GPU for GUI and stepgens all in one device. But you'll still need some output protection like you'll find on the Mesa IO boards.

I've had the Trinamic TMC2209's running in velocity mode over UART. Really neat but lacks the internal feedback of the software step generator. Of course counting step pulses on the diag pin or an encoder to close the loop would be solutions. But then needs software or hardware counting modules.

The testing branch of Remora firmware for the LPC1768 has the TMC uart driver support.